The present invention relates generally to off-road motor vehicles, such as utility or recreational vehicles, and more particularly, to a suspension mechanism for the rear axle of an off-road utility vehicle.
Small off-road vehicles such as utility or recreational vehicles are becoming popular for recreational and other general purpose off-road usage. Such utility vehicles can be found in U.S. Pat. No. 4,706,770. These utility vehicles have found usage on golf courses and at sporting events, and are particularly adaptable for utilization on a farm. This type of flexibility in the wide variety of uses necessitates a vehicle that is highly flexible, highly maneuverable and the like. This demands a vehicle that will afford a high degree of maneuverability and ease of steering.
Steering characteristics of known utility vehicles provide poor turning performance. Known utility vehicles have turning clearance circles having a diameter greater than twenty-one feet. The use of independent front wheel suspension mechanisms on known utility vehicles, coupled with the mounting of the rack and pinion systems on the frame of the vehicle, introduces minor king pin rotations as the steering tires ride over ground undulations. Such construction reduces steering precision and can accelerate the wear of the tires on the steering axle.
Placing a load on the utility vehicle typically results in a variation in the steering performance of known utility vehicles. For example, one known embodiment having a front steering axle, a rear drive axle, and a middle drive axle carries the load placed on the vehicle on the middle and rear axles, resulting in proportionately less weight on the steering axle and a reduction in maneuverability. Accordingly, known utility vehicle construction results in a significant influence on the steering performance by the load carried on the vehicle. Preferably, loads should not change the steering characteristics for any vehicle.
Furthermore, conventional utility vehicle construction mounts both the middle and rear axles directly to the frame of the vehicle, resulting in a harsh ride characteristic and direct application of any load placed into the load bed onto the middle axle as well as the rear drive axle. It would, therefore, be desirable to enhance the ride characteristics, as well as the steering performance of utility vehicles by providing a suspension mechanism for the rear axle and by distributing the weight of the loads being carried between the front and middle axles.
It is therefor desirable to provide a utility and recreational vehicle that overcomes the disadvantages of the known prior art utility vehicles.
Accordingly, an important object of the present invention is to provide a rear axle suspension mechanism for a utility vehicle having a bogey beam apparatus interconnecting the front and middle axles.
It is another object of this invention to provide a support mechanism for the middle axle on a utility vehicle to provide flotational movement of the middle axle relative to the frame.
It is a further object of this invention to provide support for the middle axle of a utility vehicle in such a manner as to prevent the load placed thereon from overcoming the steering operation of the front axle.
It is a feature of this invention to add a bogey beam extending longitudinally at the center line of the utility vehicle to interconnect the front and middle axles.
It is another feature of this invention that a portion of the load placed into the load bed of the utility vehicle will be distributed to the bogey beam to be re-distributed to the front and middle axles in a predetermined proportion.
It is an advantage of this invention that maneuverability of the utility vehicle is maintained during load bearing operations.
It is a another advantage of this invention that the middle axle provides the ability to oscillate and float relative to the frame of the utility vehicle.
It is still another advantage of this invention that the ride characteristics of a utility vehicle are improved, particularly under load bearing conditions.
It is still another feature of this invention that the loads placed on the load bed of the utility vehicle are proportionally distributed between the front steering axle and the middle drive axle of the utility vehicle.
It is a yet another advantage of this invention that the Rotational movement of the middle axle provides sufficient slack in the drive mechanism to permit the chain drive to twist slightly in response to the oscillation of the middle axle.
It is yet another feature of this invention that a central support bracket pivotally connecting a support beam for the middle axle to the bogey beam allows a Rotational movement of the middle axle with the bogey beam and with longitudinally stabilizing support links.
It is yet another object of this invention to provide a suspension mechanism for the rear axle that is cooperable with the configuration of the middle and front axles interconnected by a bogey beam.
It is a further feature of this invention that the ride characteristics of a utility vehicle are greatly improved by a suspended rear axle and a load distributing bogey beam interconnecting the front and middle axles.
It is still a further feature of this invention that the middle and rear axles are independently movable relative to the frame of the utility vehicle to enhance the ride characteristics of the vehicle.
It is a further advantage of this invention that the middle and rear axles can be operatively powered to drive the utility vehicle over the surface of the ground.
It is a further object of this invention to provide a rear axle suspension mechanism for an off-road vehicle that is durable in construction, inexpensive to manufacture, carefree in maintenance, easy to assemble, and simple and effective in use.
These and other objects, features, and advantages are accomplished according to the present invention by providing a utility vehicle having a middle axle that is mounted at the end of a bogey beam for flotational movement relative to the frame of the vehicle. The rear axle is carried by a suspension mechanism supported from the frame of the vehicle. The middle axle is formed by a pair of stub axles interconnected by a support beam that is pivotally connected to the rearward end of the bogey beam. The rear suspension mechanism includes a pair of transversely spaced suspension struts interconnecting the frame and a rear axle member having the rear drive wheels mounted thereon. Connecting support links interconnect the middle and rear axles maintain proper positional spacing between the middle and rear axles.
The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention.